Diaphragm for acoustical apparatus.



No. 685,429. Patented Oct. 29, lam.

a. OSTEN & w. P. SPALDING.

DIAPHRAGM FOR ACOUSTIC-AL APPARATUS.

(Application filed Feb. 5, 1901.)

(No Model.)

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THE womns mzus co. wow-umov, wuumswon D c UNITED STATES PATENT OFFICE.

GEORGE OSTEN AND \VILLIAM P. SPALDING, OF DENVER, COLORADO.

DIAPHRAGM FOR ACOUSTICAL APPARATUS.

SPECIFICATION forming part of Letters Patent No. 685,429, dated October29, 1901.

Application filed February 5,1901. Serial N0. 46,129. (No model.)

To all 2071 0171, it may concern:

Be it known that we, GEORGE OSTEN and WILLIAM P. SPALDING, residents ofDenver, Colorado, have invented a new and useful Improvement inDiaphragms for Acoustical Apparatus, which invention is fully set forthin the following specification.

The object of this invention is to provide a diaphragm for use in therecorders and reproducers of sound recording and reproducing apparatus,Which will possess vibratory properties of superior delicacy andaccuracy, enabling sounds to be truthfully recorded and reproduced evenas to their minutest details. This object is attained by making thediaphragm, either in whole or in part, of a specially-prepared paper,such as hereinafter described. The paper, preferably wood-pulp paper, isfirst submerged in a solution of bicarbonate of soda in distilled water,where it is allowed to remain for several hours in a Warm place. Theeffect of this solution is to neutralize or destroy all foreign matterin the paper which would be detrimental to its vibratory properties. Atthe same time the paper by absorbing the solution acquires aleather-like toughness. After its removal from the bicarbonate solutionthe paper is submerged for several hours in distilled water forcleansing purposes. The paper is next submerged and let stand for anhour or more in a solution of chlorid of gold-from one to one and a halfounces of distilled water to two or three grains of chlorid of gold.After removal from the gold solution and drying the paper is placed in asolution of from one hundred and fifty to two hundred grains of nitrateof silver and one to two grains of cyanid of potassium in one and a halfto two ounces of distilled water and let remain for from five to eighthours. The effect of the gold and silver solutions is to thoroughlyimpregnate the paper With deposits of these metals, imparting theretothe desired metallic properties The cyanid of potassium acts to causethe paper to absorb the solution more readily and quickly. After thepaperis removed from the silver solution and has become nearly but notentirely dry it is placed between two pieces of perfectly clean paperand covered .with a warm smooth heavy weight for example, an ordinarysmoothing-iron for clothes-until thoroughly dry, when it is placed whereair can circulate about it.

In order to preserve the paperfrom effects of the weather, either wet ordry, cold or heat, an oily substance, such as pure white wax, is appliedthereto. The oily substance also has the efiect of removing excessivemetallic sounds.

It will of course be understood that the proportions of the materialswith which the paper is treated may be varied as desired and that theprocedure may be varied within wide limits, the principal purpose beingto impart to the paper the leather-like toughness and metallicproperties.

YVhile paper is preferred, other suitable fibrous materials treated inthe manner above indicated may be employed in the construction ofdiaphragms according to the invention. In utilizing thisspecially-prepared paper or fibrous material in the construction ofdiaphragms for acoustical apparatus the vibratory body or part, which ismade of said material, may constitute the whole or only a part of thediaphragm, greatly improved results being attained in either case.

The accompanying drawings illustrate several forms of diaphragmsembodying this invention.

Figure l is a plan View of a diaphragm made entirely of thespecially-prepared pa per. Fig. 2 is a plan view of another form ofdiaphragm. Figs. 3 and at are details illustrating the paper center andsupporting-ring, respectively, of the diaphragm of Fig. 2; and Fig. 5 isa plan view of still another form of diaphragm.

As already stated, the diaphragm A of Fig. 1 is made entirely of thespecially-prepared paper.

In the diaphragm of Figs. 2, 3, and 4E the vibratory body B is made ofthe speciallyprepared paper and cemented to an outer supporting ring orframe 0, of suitable material, preferably of mica. The cement used ispreferably a paste of white shellac and al cohol. In applying the pastethe edge of the paper center 13 is roughened where it overlaps the ring0, so that the cement will take holda The mica ring serves as a bearingfor the means for clamping the diaphragm in place in a recorder orreproducer and is less likely to be injured than if the clamping meansacted directly upon the paper.

In Fig. 5 the diaphragm consists of a body or annulus F of thespecially-prepared paper. Annulus F is cemented at its inner edge to acentral plate D, of very thin metal, and at its outer edge to asupportingq'ing E, of mica, metal, or other suitable material.

Although specially designed for use in sound recording and reproducingapparatus, diaphragms embodying this invention may be employed in otherapparatus where diaphragms are adapted to be acted upon by soundvibrations.

What We claim is 1. In acoustical apparatus, avibratory body consistingof fibrous material impregnated with metal.

2. A vibratory body for acoustical apparatus consisting of fabric offibrous material impregnated with metal.

3-. In acoustical apparatus, a vibratory body consisting of paperimpregnated with metal.

4. In acoustical apparatus, a vibratory bod y consisting of toughenedfibrous material impregnated with metal.

5. In acoustical apparatus a vibratory body consisting of toughenedpaper impregnated with metal.

6. A Vibratory body for use in acoustical apparatus consisting of paperimpregnated with gold and silver.

7. A vibratory body for use in acoustical apparatus consisting oftoughened paper 1111- pregnated with gold and silver.

8. A vibratory body for use in acoustical apparatus consisting of papertoughened by the action of a solution of bicarbonate of soda andimpregnated with gold and silver by the action of a solution of chloridof gold and a solution of nitrate of silver.

9. A vibratory body for use in acoustical apparatus consisting oftoughened paper impregnated with metal, and having applied thereto anoily substance.

10. A diaphragm for use in acoustical apparatus consisting of avibratory body of toughened fibrous material impregnated with a metaland having a supporting frame around its outer edge.

11. A diaphragm for use in acoustical apparatus consisting of avibratory body of fibrous material impregnated with a metal having asupporting-frame around its outer edge and a thin metallic centralplate.

12. In a diaphragm for use in acoustical apparatus, an annular vibratorybody of toughened fibrous material impregnated with a metal having athin metallic central plate.

In testimony whereof we have signed this specification in the presenceof two subscribing witnesses.

GEORGE OSTEN. WU. P. SPALDING. lVitnesses:

MARY J ONES, JESSIE D. THOMPSON.

